This invention relates intravascular catheters, and more particularly to micro catheters and guidewires that access tortuous regions of the vasculature.
There is a demand for increasingly smaller diameter catheters to enable access to tortuous regions of the vascular system such as regions of the neurovasculature.
Tortuous regions of the vasculature are defined as regions having vessels that branch off from more proximal vessels at angles of greater than 90 degrees. Portions of the vessels have lumen diameters of 3 mm or less. Micro catheters are defined as those catheters capable of navigating through these tortuous regions. There are limitations to the functionality of existing micro catheters.
One limitation relates to pushability of micro catheters. Typically micro catheters are inserted into the vasculature with a guiding catheter. As micro catheters evolve into smaller sizes, it is found that a micro catheter can kink or buckle when tracking via the guiding catheter. Kinking and buckling of a micro catheter are not desirable qualities.
Many micro catheters have a braided catheter body to reinforce the catheter body, optimizing catheter pushability and thereby inhibiting buckling. Current braided catheter technology has proved useful with the larger micro catheters; e.g. micro catheters having a 0.032xe2x80x3 distal shaft diameter and larger.
Braided catheters, particularly for micro catheters having distal shaft diameters of less than 0.032xe2x80x3, are expensive to manufacture and may be cost prohibitive to use regularly. Braided catheters may not bend well enough for use in the most distal and tortuous regions of the vasculature. What is desired is a micro catheter that has a high degree of axial compressive strength (pushability) and the capability to bend through tortuous regions of the vasculature. What is also desired is a micro catheter that resists kinking and buckling.
A micro catheter and guidewire system for use in tortuous regions of a vasculature includes a catheter body having a distal end, a guidewire lumen, a proximal region with an outer diameter, and a distal region with an outer diameter.
The ratio of the proximal region outer diameter to the distal region outer diameter is at least 1.625:1 to strengthen the proximal region, thereby improving the overall integrity of the catheter body. Increased torque capability, improved pushability and increased control of the catheter body result from forming the catheter body according to this ratio. Strengthening the proximal region further enables the catheter body to resist kinking and buckling during use.
The guidewire lumen defines a stopper and the guidewire has a depth stop for engaging the stopper of the guidewire lumen. The stopper in the guidewire lumen and depth stop on the guidewire enable the guidewire to selectively and compositely cooperate with the catheter to improve catheter pushability when the depth stop and the stopper engage.
The depth stop and stopper cooperate to prevent over extension of the guidewire when the guidewire and catheter body simultaneously push through tortuous regions of the vasculature.
The guidewire lumen defines a pathway between the guidewire and the guidewire lumen to facilitate infusion of fluids including contrast agents, blood thinners, nutrients, and medicine through the distal end of the catheter body. This is important because a separate infusion lumen, which consumes space, is not necessarily required. The depth stop and stopper function as a valve to prevent the infusion of fluid via the pathway.